Blood Tests & Screenings

Question 1

What is the aim of screening?

Answer 1

aims to identify people who are at risk of having a particular disease or medical condition before they show any sign of having it

Question 2

Why does it mean when you are divided into low and high chance groups?

Answer 2

high risk groups will be offered further tests to find out if they have a particular condition or not

Question 3

Explain ‘the sieve’

Answer 3

Everyone taking the test, some get caught in the sieve and referred for further tests. Low risk people get sieved through.

Question 4

Terminology: define false positive

Answer 4

wrongly reported as having the condition

Question 5

Terminology: define false negative

Answer 5

wrongly reported as not having the condition

Question 6

How do you give ‘informed choice? about screening tests?

Answer 6

• explain it’s optional
• check understanding of screening versus diagnosis
• explain how the tests are done
• explain and agree how and when results will be given
• discuss the meaning of the potential test results
• document decision

Question 7

What antenatal screening tests are offered in the UK?

Answer 7

• blood - sickle cell and thalassaemia
• infectious diseases - syphillis, hep B, HIV
• fetal anomalies - downs, edwards, pataus

Question 8

When are women offered screening for SCD and Thal.?

Answer 8

by 8-10 weeks gestation (at booking)

Question 9

Observing a high or low prevalence of SCD or Thal. What is it based on?

Answer 9

family origin and blood results

Question 10

If pregnant women are identified as a carrier of SCD or Thal, what happens next?

Answer 10

The baby’s father will be offered the screening asap

Question 11

If both parents are identified as a carrier of SCD or Thal what is offered to them and their baby?

Answer 11

• referral for counselling
• offer prenatal diagnosis by 12+6 gestation
• all babies offered screening for SCD through heel prick test postnatal day 5

Question 12

What infectious diseases are screened for in pregnancy?

Answer 12

HIV, Hepatitis B and Syphilis

Question 13

What care is to be given to women screened positive for infectious diseases?

Answer 13

referred for appropriate specialist care in line with programme standards

Question 14

What care is to be given to babies born to mothers with HIV and syphilis?

Answer 14

Should be followed at birth in line with clinical guidelines

Question 15

What care is to be given to babies born to mothers with Hepatitis B?

Answer 15

Vaccinated within 24 hours of birth and referred for follow up vaccinations 1, 2 and 12 months old with a blood test to test the effectivity status of the vaccine

Question 16

What 3 main fetal anomalies are screened for?

Answer 16

Down Syndrome, Edward’s and Patau’s

Question 17

What does the combined test involve?

Answer 17

A blood test and nuchal translucency ultrasound scan

Question 18

When is a combined test done?

Answer 18

between gestation 11-14

Question 19

What is the use of blood and NT test in the combined test screenings?

Answer 19

blood - measure levels of substances found in the blood

NT - measure fluid at the back of baby’s neck

Question 20

When you are a late booker, what test is offered to you for fetal anomalies?

Answer 20

Quadruple test between gestation 14-20

Question 21

What are potential problems of the quadruple test?

Answer 21

• only screens for Downs

- reduces choices of termination

Question 22

What are the two diagnostic ‘further’ tests for high chance babies?

Answer 22

Amniocentesis

Chorionic Villus Sampling

Question 23

What is amniocentesis?

Answer 23

removing a small amount of fluid from around the baby (amniotic fluid) using a fine needle. Usually performed after 15 weeks of pregnancy.

Question 24

What is Chorionic Villus Sampling (CVS)?

Answer 24

Removing a tiny sample of the placenta using a fine needle. Usually permoed between 11-14 weeks.

Question 25

What are the risks of the diagnostic/’further’ tests?

Answer 25

1-2 in 100 chance of miscarriage

Question 26

List other anomalies screened for?

Answer 26

• open spina bifida
• anencephaly
• cleft lio
• diaphragmatic hernia
• gastroschisis
• exomphalos
• cardiac anomalies
• bilateral renal agenesis
• lethal skeletal dysplasia
• trisomy 18 or 13

Question 27

What is open spina bifida?

Answer 27

no skin covering, bottom of the spinal cord exposed

Question 28

What is gastroschisis?

Answer 28

intestines on the outside of the baby’s body

Question 29

What is exomphalos?

Answer 29

intestines on the outside of baby’s body in the sac

Question 30

What is anencephaly?

Answer 30

absence of major portion of brain, skull and scalp

Question 31

When are haemoglobin levels tested and why?

Answer 31

at booking and 28 weeks to screen for anaemia to enable iron treatment if necessary

Question 32

When is blood group and rhesus status tested and why?

Answer 32

Booking and 28 weeks to determine whether anti-D is necessary

Question 33

When is syphilis tested?

Answer 33

at booking to begin necessary treatment

Question 34

When is SCD and thalassaemia treated?

Answer 34

by 10 weeks (at booking usually)

Question 35

When is HIV tested and why?

Answer 35

At booking so interventions can be offered to infected women

Question 36

When is Hepatitis B tested and why?

Answer 36

at booking so postnatal can be offered to infected women and babies!

Question 37

What are some advantages to screening?

Answer 37

• informed choice
• preparation for birth and parenthood
• counselling opportunities

Question 38

What are some disadvantages to screening?

Answer 38

• not 100% accurate

- anxiety around the tests and the result